Theoretical Prediction of Chiral 3D Hybrid Organic–Inorganic Perovskites

Hybrid organic–inorganic perovskites (HOIPs), in particular 3D HOIPs, have demonstrated remarkable properties, including ultralong charge‐carrier diffusion lengths, high dielectric constants, low trap densities, tunable absorption and emission wavelengths, strong spin–orbit coupling, and large Rashba splitting. These superior properties have generated intensive research interest in HOIPs for high‐performance optoelectronics and spintronics. Here, 3D hybrid organic–inorganic perovskites that implant chirality through introducing the chiral methylammonium cation are demonstrated. Based on structural optimization, phonon spectra, formation energy, and ab initio molecular dynamics simulations, it is found that the chirality of the chiral cations can be successfully transferred to the framework of 3D HOIPs, and the resulting 3D chiral HOIPs are both kinetically and thermodynamically stable. Combining chirality with the impressive optical, electrical, and spintronic properties of 3D perovskites, 3D chiral perovskites is of great interest in the fields of piezoelectricity, pyroelectricity, ferroelectricity, topological quantum engineering, circularly polarized optoelectronics, and spintronics.     

减振器在自导系统结构设计中的应用

通过对减振器结构设计的理论分析，建立了减振器的数学模型，同时通过设计的模拟装置对减振效果进行了实测，效果良好。     

Asymmetric Hydrogenation of Activated Ketones on Platinum: Relevant and Spectator Species

The heterogeneous enantioselective hydrogenation of activated ketones over chirally modified platinum is reviewed with emphasis on identifying the role of the various species observed in this catalytic system. The past years have witnessed a continuous broadening of the scope of this catalytic system including new reactants and modifiers affording over 97% ee. New reaction pathways have been uncovered and the kinetic and mechanistic studies have been faced with a number of complicating factors caused by spectator species and interactions in solution and on the Pt surface. The previously proposed mechanistic models are critically assessed in the light of these new findings.     

垂直管吸收器内泡式吸收过程的数值研究

建立垂直管吸收器管内泡式吸收过程中传热传质的数学物理模型，对其泡式吸收过程进行数值研究，获得泡式吸收方式的一些传热传质特性，为吸收器的优化设计提供一定理论指导。     

有限周期梁用动力消振器抑振的特性

本文用弯曲波方法导出了多支承梁加动力消振器位移响应的普遍表达式。理论分析发现了周期结构用动力消振器抑制振动的一些新特性：（１）仅用一个动力消振器可抑制周期结构对应传递频带内的一组共振峰。被抑制的共振峰的数量与跨距的数量和消振器的布置位置有关；（２）动力消振器调谐频率与对应传递频带的第一个共振频率相关联。当动力消振器与作用在梁上的外载荷作用在同一点时，最佳调谐频率比总是大于１，否则最佳调谐频率比小于１。     

利用高酸值餐饮废油脂制备生物柴油

以高酸值餐饮废油脂为原料,在酯化反应后再经两步酯交换反应制备生物柴油。在酯化反应中添加吸水剂可降低油脂的酸值,经一次酯化反应即可将油脂的酸值降至2m g/g左右,满足酯交换反应的要求。考察了酯化反应中吸水剂的添加方式、种类及其用量对酯化反应的影响,以及酯交换催化剂的种类及用量对脂肪酸甲酯(FAME)收率和产物组成的影响。实验结果表明,以凹凸棒土为吸水剂(用量为餐饮废油脂中游离脂肪酸质量的3%),且在酯化反应30m in时加入,酯化效果较好;以质量比为1∶1的NaOH和KOH混合物为催化剂进行两步酯交换反应时,催化剂的最佳用量依次为1.00%和0.75%(质量分数,基于油脂的质量),FAME收率最高达到96.33%。     

An Investigation of Vibration Reducing on a Machine Tool

In order to reduce the vibration on a machine tool, more orthogonal experiment schemes have been designed, which are based on the steel balls vibration reducing principle. After experiments the optimal reducing vibration scheme was determined. This kind of vibration reducing scheme is used in steel balls vibration absorber, which can be used to reduce vibration magnitudes of a machine tools under the working conditions, whereby improving machining precision. The suggested experiment method is of useful reference in reducing vibrations on other machine tools too.     

自调Q掺饵光纤激光器

研制出一种结构新颖的掺饵光纤激光器，该激光器利用线性光纤环形镜和半导体激光器芯片的背向反射镜组成谐振腔。采用半导体激光器芯片作为饱和吸收体，在９ｍＷ的泵浦功率下，该激光器实现了自调Ｑ脉冲输出。输出光脉冲宽度为１２μｓ，脉冲峰值功率约为２２ｍＷ，脉冲序列的重复周期约为６５μｓ。